Title: ====== Paypal Bug Bounty #102 QR Dev Labs - Auth Bypass Vulnerability Date: ===== 2013-07-05 References: =========== http://www.vulnerability-lab.com/get_content.php?id=995 PayPal Security UID: ZVf25kC VL-ID: ===== 995 Common Vulnerability Scoring System: ==================================== 7.1 Introduction: ============= Shopping made easy with PayPal QR enabled on your mobile device. You can scan for deals using the QR Code displayed in shops, trains stations, bus-stops & banners and purchase items in just a few taps. Make shopping experience easy for your customer. (Copy of the Vendor Homepage: https://qr.paypal-labs.com ) Abstract: ========= An independent vulnerability laboratory researcher discovered an auth bypass web session vulnerability in the PayPal QR Labs Service Web Application. Report-Timeline: ================ 2012-05-11: Researcher Notification & Coordination (Cernica Ionut) 2013-05-14: Vendor Notification (PayPal Inc Security Incident Team - Bug Bounty Program) 2013-06-20: Vendor Fix/Patch (PayPal Inc Developer Team) 2013-07-05: Public Disclosure (Vulnerability Laboratory) Status: ======== Published Affected Products: ================== PayPal Inc Product: QR Labs Online Service - Web Application 2013 Q2 Exploitation-Technique: ======================= Remote Severity: ========= High Details: ======== An auth bypass session web vulnerability is detected in the official PayPal QR Labs Service Web Application. The vulnerability allows remote attackers to bypass the web- or system user auth of the affected vulnerable computer system to compromise paypal accounts. The bug is located in the application account login module when processing to load manipulated j_password parameters via GET method. Attackers are able the decrypt and exchange the information in the request live with a session tamper to take-over other accounts. At the end the vulnerability allows remote attackers to enter remotely any paypal qr labs account of the web application. Exploitation of the vulnerability does not require user interaction but a low privileged paypal qr labs application user account. Successful exploitation results in account steal or compromise and stable user session manipulation with different effects. Vulnerable Service(s): [+] PayPal Inc – qr.paypal-labs.com Vulnerable Module(s): [+] Account - Login Vulnerable Parameter(s): [+] j_password Affected Module(s): [+] Account System Proof of Concept: ================= The vulnerability can be exploited by remote attackers with low privilege paypal qr labs application user account and without user interaction. For demonstration or reproduce ... Note: After some security checks to authenticate in the qr.paypal-labs.com web application, the last request for being authenticate in this web application it is not secure implemented. Afected Link: https://qr.paypal-labs.com/j_security_check?j_username=loger177@gmail.com&j_password=96301aa9f02b5d12278b0e902dc5434ed9477d19 Note: If we look at the request wich is a GET method request we will soon see ... If we encrypt the j_username parameter value as SHA1 ... The result will be the value of the j_password parameter Note: PoC Video The username loger177@gmail.com is encrypted in SHA1 it is equals with < 96301aa9f02b5d12278b0e902dc5434ed9477d19 In the demonstration above it seems that the password of the username is encrypted in SHA1 ;) Solution: ========= 2013-06-20: Vendor Fix/Patch (PayPal Inc Developer Team) Risk: ===== The security risk of the auth bypass web session vulnerability is estimated as high(+). Credits: ======== Independent Security Researcher – Cernica Ionut Cosmin (ionut.cernica@whit3hat.com) Disclaimer: =========== The information provided in this advisory is provided as it is without any warranty. Vulnerability-Lab disclaims all warranties, either expressed or implied, including the warranties of merchantability and capability for a particular purpose. Vulnerability- Lab or its suppliers are not liable in any case of damage, including direct, indirect, incidental, consequential loss of business profits or special damages, even if Vulnerability-Lab or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. We do not approve or encourage anybody to break any vendor licenses, policies, deface websites, hack into databases or trade with fraud/stolen material. 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